Abstracts From Complex Cardiovascular Catheter Therapeutics (C3) Advanced Endovascular and Coronary Intervention Global Summit

Complex Cardiovascular Catheter Therapeutics (C3) Advanced Endovascular and Coronary Intervention Global Summit is an annual conference that addresses educational needs in the diagnosis and treatment of peripheral arterial, carotid, venous, coronary and aortic aneurysm diseases. C3 is designed for interventional cardiologists and vascular surgeons, as well as fellows, residents, podiatrists, radiologic technologists, and other healthcare professionals interested in atherosclerotic cardiovascular disease. This conference offers opportunities for learners to view didactic lectures and panel discussions, as well as debate and discussion of prerecorded and live case studies.

The upcoming C3 conference takes place June 14-18, 2015 at Hilton Bonnet Creek in Orlando, Florida. Website: www.c3conference.net

J INVASIVE CARDIOL 2015;27(4):E56-E59

Key words: coronary artery calcification, rotational atherectomy, cost

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Identification of Coronary Plaque Composition and Subtype Using Optical Coherence Tomography is Affected by Interobserver Variability

Adam J. Brown, Catherine Jaworski, Ramesh Da Silva, Joseph P. Corrigan, Martin R. Bennett, Michael Mahmoudi, Stephen P. Hoole, and Nick E.J. West

Background. Autopsy studies have suggested that thin-cap fibroatheroma (TCFA) is the precursor lesion for the majority of myocardial infarctions. However, identification of TCFA in vivo remains a major diagnostic challenge. Optical coherence tomography (OCT) has emerged as a novel, invasive imaging modality that has potential to permit plaque classification through identification of compositional features, including lipid, calcification and fibrous cap thickness. However, the subtle changes in light attenuation as the beam transverses the plaque can be challenging to interpret, with consequent potential for significant operator error and plaque misclassification.  

Methods. OCT imaging (Dragonfly C7; St Jude Medical) was performed on 38 patients prior to percutaneous coronary intervention. Analysis was performed offline on a LightLab Imaging (St Jude Medical) workstation by two independent, experienced OCT operators. Luminal dimensions and plaque compositional features were assessed at the minimal luminal area (MLA) and at five 1 mm longitudinal intervals both proximal and distal to the MLA. An OCT fibroatheroma was defined as plaque with >90° lipid arc, while an OCT-TCFA was defined as a fibroatheroma where the minimal fibrous cap thickness was <0.85 μm. Interobserver agreements for continuous variables were assessed using absolute intra-class correlation coefficients, with Cohen’s Kappa used for categorical data.

Results. Overall, a total of 410 frames of OCT from 38 coronary plaques were included in the analysis. There was exceptional consistency between observers for mean, maximal, and minimal luminal dimension (all r > 0.98 and P<.001), and luminal area (r = 0.99; 95% CI, 0.99-1.00; P<.001). Interobserver agreement for plaque compositional arc was stronger for calcification (r = 0.80, 95% CI 0.73-0.86; P<.001) than lipid (r = 0.71; 95% CI, 0.62-0.79; P<.001), while agreement on minimal fibrous cap thickness was moderate (r = 0.55; 95% CI, 0.41-0.66; P<.001). For plaque classification, operator agreement for both an OCT-defined fibroatheroma (Kappa 0.64) and an OCT-TCFA (Kappa 0.67) was good. 

Conclusions. Luminal dimensions and areas are consistently measured by OCT. In contrast, measures of plaque compositional features and classification are affected by interobserver variability.  Although measurement of minimal fibrous cap thickness appears particularly prone to disagreement, the ability of operators to classify an OCT-TCFA is not reduced. These findings suggest that OCT may reproducibly identify TCFA in vivo.

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Acute and 30-Day Outcomes of Orbital Atherectomy to Prepare De Novo, Severely Calcified Coronary Lesions in Patients With Reduced Left Ventricular Ejection Fraction

Jeffrey W. Chambers, Arthur C. Lee 

Background. Current data are conflicting on the superiority of coronary artery bypass grafting (CABG) or percutaneous coronary intervention (PCI) in patients with abnormal ventricular function. Current American Heart Association guidelines state that there are insufficient data to make a recommendation regarding the role of PCI in patients with left ventricular dysfunction. Historically, reduced left ventricular ejection fraction (LVEF) has been a risk factor for adverse in-hospital and long-term outcomes post PCI, including increased risk of stent thrombosis and lower survival rates post procedure compared to patients with normal left ventricular function.In this analysis, we evaluate the procedural and 30-day outcomes based on baseline LVEF in the ORBIT II trial.

Methods. The ORBIT II trial, a prospective, multicenter, non-blinded clinical trial that enrolled 443 patients, was designed to evaluate the safety and efficacy of the coronary Orbital Atherectomy System to prepare de novo, severely calcified coronary lesions for stent placement. Procedural and 30-day outcomes for patients with LVEF ≤40% (n = 33), LVEF 41%-50% (n = 90), and LVEF >50% (n = 314) were evaluated in this analysis. In the ORBIT II study, major adverse cardiac event (MACE) was defined as a composite of cardiac death, myocardial infarction (MI, CK-MB >3x the upper limit of normal) and target vessel revascularization (TVR). 

Results. There was a difference in the distribution of male gender (84.8% vs 75.6% vs 59.9%; P=.01), prevalence of diabetes mellitus (42.4% vs 46.7% vs 33.1%; P=.049), history of MI (51.5% vs 36.7% vs 15.3%; P<.001), and history of CABG (33.3% vs 17.8% vs 11.8%; P=.005) across the LVEF ≤40%, LVEF 41%-50%, and LVEF >50% groups, respectively. The rate of procedural success (stent delivery with residual stenosis <50% without the occurrence of an in-hospital MACE) was similar in all groups (90.9% vs 88.9% vs 88.4%; P>.99). As estimated by Kaplan Meier at 30 days, patients with LVEF ≤40%, LVEF 41%-50%, and LVEF >50%  had similar low rates of MACE (9.1% vs 7.8% vs 11.5%; P=.60), MI (9.1% vs 6.7% vs 10.8%; P=.53), TVR (0% vs 1.1% vs 1.6%; P=.95) and cardiac death (0% vs 0% vs 0.3%; P>.99), respectively.

Conclusions. Preparation of severely calcified coronary lesions with the coronary Orbital Atherectomy System facilitated stent delivery in patients with reduced LVEF with low rates of 30-day MACE, MI, cardiac death, and TVR. Further studies are needed to better understand the impact of left ventricular dysfunction on the treatment of severely calcified coronary artery disease.

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A Novel Multi-Lumen Compliant Balloon Catheter Preserves Stem Cell Viability and Decreases Cellular Clumping When Compared to a Standard Single

Lumen Balloon Angioplasty Catheter 

Nabil Dib, John Abraham, Brian Plourde, Dillon Schwalbach, DeAnn Dana, Lester Myers, Katherine Hunkler, Todd Flower, Rob Kohler

Background. Intracoronary stem cell (SC) infusion is typically administered through a single-lumen balloon angioplasty catheter (SLC). These catheters are not optimized for SC delivery and potentially compromise SC viability and effectiveness. A multi-lumen catheter (MLC), the ND Infusion Catheter, may offer clinical advantages by preserving cell viability (CV) and reducing cellular clumping that might lead to embolization.

Method. A standard .014˝ over-the-wire SLC was compared to a novel MLC 3 Fr .014˝ rapid-exchange catheter with 6 micro-lumens that act as cell separators. Computational fluid dynamic modeling was used to calculate shear stress and predict CV at infusion rates of 1 and 4 mL/minute at various balloon inflations. Mesenchymal SCs at concentrations of 5 x 10⁶/mL were tested for viability using trypan blue pre and post injection through the SLC and MLC during balloon inflations of 6, 8, 10, and 12 atm. Microscopy was used to assess cellular separation after cell injection for both catheters.

Results. Collapsing of the SLC infusion lumen was noted during balloon inflation, while no changes were noted in the MLC infusion lumen. Computational fluid dynamic calculations in the SLC demonstrated significant increase of 2979 Pascal in fluid shear stress. As balloon pressure increased in the SLC, the infusion lumen collapsed, whereas fluid shear stress in the MLC was 43 Pascal. CV decreased in the SLC at a flow rate of 1 mL/min from 97.5% to 91.7%, 95.7% to 94.1%, 94.9% to 86.8%, and 97.9% to 76.9% at 6, 8, 10, and 12 atm, respectively (P=.047). Repeated experiments showed variability in CV for the SLC, but in all cases CV decreased depending on inflation pressure. At 4 mL/min, cell survival decreased using the SLC from 92.2% to 62% and 91.3% to 60.8% at 8 and 12 atm, respectively, while no significant change in CV occurred using MLC resulting in 93.5% to 92.3%, 95% to 93.1%, 95% to 94.6%, and 93.2% to 97.3% at 6, 8, 10, and 12 atm, respectively (P=.90). Overall, CV post injection was 86.4% and 94.4% (P=.01) for SCL and MLC, respectively. Microscopy demonstrated improved cell separation during infusion with the MLC compared to the SLC.

Conclusion. A novel multi-lumen catheter can aid in safer SC delivery by preserving cell viability, and minimizing cellular clumping.

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Safety and Efficacy of the Orbital Atherectomy System in Treating De Novo, Severely Calcified Coronary Lesions in Patients With and Without Diabetes Mellitus: A Sub-Analysis of the ORBIT II Clinical Trial

 Jeffrey W. Chambers, Arthur C. Lee

Background. Patients with diabetes mellitus (DM) are at high-risk for severe coronary artery calcification. Severely calcified lesions make successful balloon angioplasty and stent delivery more difficult during percutaneous coronary intervention and treatment may lead to serious procedural complications. In this analysis, we investigate the safety and efficacy of the Diamondback 360 Coronary Orbital Atherectomy System (OAS) (Cardiovascular Systems, Inc) to treat severely calcified lesions in patients with and without DM in the ORBIT II trial.

Methods. The ORBIT II trial, a prospective, multicenter, non-blinded clinical trial, enrolled 443 consecutive patients at 49 United States sites. The primary safety endpoint (freedom from major adverse cardiac event [MACE] at 30 days post procedure) and the primary efficacy endpoint (procedural success defined as stent delivery with a residual stenosis of <50% without the occurrence of an in-hospital MACE) were evaluated in diabetic (DM group; N = 160) and non-diabetic (No-DM group; n = 283) patients. In the ORBIT II trial, MACE was defined as a composite of cardiac death, myocardial infarction (MI, CK-MB >3x the upper limit of normal), and target vessel revascularization (TVR).

Results. Patients with DM were younger (70.3 years vs 72.0 years; P=.02) and had higher body mass index (31.0 vs 28.5; P<.001). In addition, history of hypertension (96.3% vs 89.0%; P=.01) and previous coronary artery bypass graft (20.0% vs 11.7%; P=.02) were more prevalent in the DM group. Stent delivery occurred successfully in 96.9% and 98.2% of subjects (P=.51) with <50% residual stenosis in 98.7% and 98.6% of subjects (P>.99) in DM and No-DM groups, respectively. At 30 days post procedure, as estimated by Kaplan Meier, DM and No-DM groups had similar low rates of MACE (8.8% vs 11.3%; P=.40), cardiac death (0% vs 0.4%; P>.99), MI (8.1% vs 10.6%; P=.40), and TVR (0.6% vs 1.8%; P=.34).

Conclusion. Although the baseline characteristics of the diabetics were worse, both the diabetic and non-diabetic groups met the ORBIT II primary safety and efficacy endpoints and had low rates of 30-day MACE. This sub-analysis suggests that the coronary OAS can be used safely to facilitate successful stent deployment in both diabetic and non-diabetic populations.

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Superficial Femoral Artery TASC D Registry: Twelve-Month Effectiveness Analysis of the Pulsar-18 SE Nitinol Stent in Patients With Critical Limb Ischemia

M. Lichtenberg, W. Stahlhoff, D. Boese

Aim. Single-center observational study analyzing the primary patency rate and freedom from target lesion revascularization (TLR) rate of the Pulsar-18 nitinol stent after recanalization of long superficial femoral artery (SFA) occlusions (TASC D) in 22 patients with critical limb ischemia (CLI).

Methods. Between 1/2011 and 7/2011, a total of 22 consecutive patients (9 male, 13 female) with chronic total occlusion (CTO) of the femoro-popliteal arteries presenting with CLI (17 patients with Rutherford 4 score, and 5 patients with Rutherford 5 score) were enrolled and successfully recanalized using the Pulsar-18 self-expanding (SE) nitinol stent (Biotronik AG). Primary patency at 12 months was defined as no binary restenosis (>50%) on Duplex ultrasound (PSVR <2.5) and no TLR performed within 12 months. The average lesion length of the treated femoro-popliteal segment was 315 mm. Performing spot stenting, average stent length in all patients was 245 mm (minimal 215 mm, maximal 315 mm).

Results. Technical success, with establishing an antegrade straight line flow to the foot through a reopened SFA, was achieved in all 22 patients. Subintimal and intraluminal recanalization techniques were used. Two patients with Rutherford 5 score had a minor  amputation shortly after the recanalization procedure. All other patients had a complete wound healing of their lesions during a 6 month follow-up. After 12-month follow-up, the primary patency rate of the Pulsar-18 SE nitinol stent was 77%, with a per protocol restenosis in 5 of 22 patients. Seventeen patients showed a walking capacity on treadmill test >300 m (Rutherford II). Two patients with a documented restenosis were Rutherford; these patients were treated conservatively. Three patients with restenosis and a Rutherford III score were scheduled for an endovascular target lesion revascularization leading to a freedom from target lesion revascularization rate of 86%.

Conclusion. Endovascular intervention of long SFA occlusions using subintimal or intraluminal recanalization technique with implantation of the Pulsar-18 SE nitinol stent in CLI patients is safe and clinically effective, with a primary patency rate after 12 months of 77% and a freedom from target lesion revascularization rate of 86%.

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Thrombectomy During Primary PCI for STEMI: Is There a Difference Between Simple Aspiration and Rheolytic Thrombectomy?

Tri Trinh, William Ng, Kevin Mak, Tiffany Wang, Michael Gaglia, Leonardo C. Clavijo, Ray V. Matthews, Anilkumar Mehra, David M. Shavelle

Routine use of thrombectomy during primary percutaneous coronary intervention (PCI) for ST-elevation myocardial infarction (STEMI) improves ST-segment recovery and myocardial perfusion and may improve mortality. The relative benefits of rheolytic thrombectomy (RT) versus aspiration thrombectomy (AT) remain unclear. The objective of this study was to compare the effectiveness of RT and AT devices in STEMI patients undergoing primary PCI.

Methods. From January 2008 through December 2012, a total of 438 patients undergoing primary PCI for STEMI were evaluated; 216 patients (49%) received thrombectomy. Patients that initially received AT (n = 199) were compared with those that received RT (n = 17). The primary endpoint was TIMI thrombus grade (TTG) 4 or 5 post thrombectomy or need for an additional thrombectomy device. Baseline demographics, TIMI flow and TTG at baseline and following PCI, occurrence of no reflow, distal embolization, and in-hospital clinical outcome were evaluated.

Results. Mean age was 57 ± 11 years and 162 (82%) were male. Demographics, comorbidities, and infarct-related artery location were similar in both groups. The primary endpoint occurred in 1/17 (5.9%) with RT and (22/199) 11% with AT (P=.51). Baseline and final TIMI flow, baseline and final TTG, no-reflow, and distal embolization rates were similar between groups (Table). In-hospital clinical events, including death, recurrent MI, stent thrombosis, and emergent revascularization, were similar between groups.

Conclusions. In our series, a simple aspiration device was used in the majority of patients undergoing thrombectomy during primary PCI for STEMI. Approximately 9% of patients receiving AT also required RT because of insufficient thrombus removal. Removal of thrombus, achievement of normal TIMI flow, and clinical events were similar between AT and RT.